Vulnerability
curl/libcurl: FTP shutdown response buffer overflow
curl might overflow a heap based memory buffer when closing down an FTP connection with long server command replies. When doing FTP transfers, curl keeps a spare "closure handle" around internally that is used when an FTP connection gets shut down since the original curl easy handle is then already removed. FTP server response data that gets cached from the original transfer might then be larger than the default buffer size (16 KB) allocated in the "closure handle", which can lead to a buffer overwrite. The contents and size of that overwrite is controllable by the server. This situation was detected by an assert() in the code, but that was of course only preventing bad stuff in debug builds. This bug is highly unlikely to trigger with non-malicious servers.
No CVSS 3.x base score yet. Since April 2026 NVD only enriches priority CVEs (KEV, federal and critical software), so most CVEs are scored only if the assigning CNA included a score in the CVE record, or by GHSA for open-source packages. Last record update .
For interim severity, fall back on KEV / EXPLOIT signals and the EPSS percentile (lower panel). Re-check this CVE after one cron tick — the score lands automatically when the source publishes.
Mid-pack — moderate exploitation likelihood.
No VEX statements published for CVE-2018-1000300. Vendors publish VEX (Vulnerability Exploitability eXchange) to assert per-product whether a CVE is actually exploitable in their distribution.
No exploitation, limited impact or prevalence